The Russian Defence Ministry said on Tuesday that Russian and Syrian military planes had not launched any air strikes on Aleppo in the last seven days, contradicting a monitor who says frontline areas in the city have been bombed since Saturday.

Russia said on Tuesday Russian and Syrian military planes had not launched air strikes on Aleppo since Moscow said it was suspending bombing seven days ago, contradicting a monitor who says air strikes on some areas resumed on Saturday.

The White House condemned the Assad regime's "defiance" of international norms after United Nations experts found the Syrian army had conducted three chemical weapons attacks against its own people in 2014 and 2015.

India and Russia on Saturday signed big-ticket defence deals, including an agreement for the 'game-changer' S-400 Air Defence System and Kamov helicopters and to replace the existing ageing fleets and build new frigates.

Syrian and Russian warplanes carried out fresh strikes on rebel-held districts of Aleppo early Thursday, after an intense bombardment over the previous two days killed at least 71 civilians, a monitor said.

Russia`s foreign ministry on Tuesday blasted what it termed "pressure" on its US-based diplomats by US intelligence, which it accused of increasingly numerous "recruitment attempts" on Moscow`s diplomatic staff.

The United States Secretary of State John Kerry criticized Russia on Tuesday for its "irresponsible and profoundly ill-advised decision" to back Syrian President Bashar al-Assad and said efforts to end the war in Syria must continue, in spite of the U.S. decision to break off talks with Moscow.